This invention relates generally to fiber optic cable, and more particularly to a method and apparatus for connecting and splicing fiber optic cables.
A number of devices have been invented for connecting and splicing fiber optic cables. Many of the designs invented for this purpose incorporate a procedure or step that permanently changes or transforms a material used to attach the fiber optic cable to the connector in its final secured position. For various reasons, including a defective attachment, it is often desired to thereafter separate the connector from the fiber optic cable so that the connector can be reused. However, when a permanent change or transformation of material used in the attachment takes place, it is often difficult to undo the connection and separate the fiber optic cable from the connector.
For example in 1979 U.S. Pat. No. 4,168,108 issued to Judeinstein disclosing a fiber optic device for connecting a fiber optic cable to a cylindrical mixer. In securing the fiber optic bundle to the connecting device, the bundle is held in place by cementing the same to a sleeve. Because the cementing step is somewhat permanent, reuse of the connector would likely be difficult. Also in 1979, U.S. Pat. No. 4,168,109 issued to Dumire showing a fiber optic connector apparatus that employs heat to cause the protective sheathing on an optic cable to flow. Once the heated material cools, the cable is maintained in an adhered condition. In this situation, the sheathing is permanently transformed at the point of attachment to make the bond.
Similarly, U.S. Pat. No. 4,730,890 issued to Kashimura in 1988 disclosing a plug set for an optical connector used with optical fiber cables. The plug set fixes and secures the cable by fixing reinforcing fibers of the optical fiber cable to a bushing with the use of thermo-shrinkable tube. Although no bonding agent such as cement or epoxy is used in this device, a thermo-shrinkable tube is permanently transformed to apply pressure on the reinforcing fibers of the fiber optic cable. Accordingly, like Dumire and Judeinstein, the Kashimura device would likely be difficult to reuse.
Some later designs, however, are directed to connectors for fiber optic cables that splice and connect the same without incorporating materials that are transformed, and without having a step in the connection process that precludes the reuse of the connector. For example in 1988 U.S. Pat. No. 4,730,892 issued to Anderson et al disclosing an optical fiber mechanical splice that employs an elastomer member that deforms to secure and align abutting optical fibers. Although a connector having this construction is reusable, and the attachment is easily reversed, the connector is not adapted for use with certain standard coupling devices and connectors presently used within the fiber optic cable industry. Similarly, in 1989 U.S. Pat. No. 4,807,957 issued to de Jong et al disclosing a connector for optical fibers that operates to couple and splice fiber optic cables independent of adhesives. In this design, spherical balls are employed to align the abutting chamfered sleeves. Like Anderson however, the device employs nonstandard construction that is not adapted for use with standard coupling devices used within the fiber optic cable industry.
Additionally, U.S. Pat. No. 4,807,958 issued to Gunner et al in 1989 disclosing a method of interconnecting optical fiber cables with the use of spherical lenses disposed at the ends of the optical fibers. Like some of the earlier designs, Gunner employs a thermo-shrinkable material in the connection process. Here, a thermo-shrinkable material is employed to form a sleeve for securing together the polyurethane sheath of the cable to a metallic collar and cylindrical body of the connector.
While all the above connection devices perform the task of connecting and splicing fiber optic cables, for reasons noted above, their performance is somewhat limited by their particular construction. Indeed, the noted connectors either employ some sort of irreversible process, including heat shrinkable materials and epoxy cements, or they are not adapted for use with certain standard coupling devices.
According, a need remains for a reusable fiber optic connector for use with common, industry accepted, coupling and splicing devices that enable an installer to perform the splicing and coupling task independent of adhesives or materials that are heat transformed.